Relaxation of vascular smooth muscle induced by low-power laser radiation.

摘要: The relaxation of rabbit aorta rings induced by low-power laser radiation was investigated in vitro to determine the location chromophore(s) responsible for this response and evaluate possible mechanisms. An action spectrum measured on thoracic precontracted with norepinephrine. decrease isometric tension during exposure light (351-625 nm) delivered via a fiber optic small spot adventitial surface. shortest UV wavelength (351 35-fold more effective than 390 nm 1700-fold 460 nm. Ultraviolet wavelengths also produced greater maximum (0.40-0.45) visible (0.20-0.25), suggesting that photovasorelaxation involves one chromophore. layer not necessary photovasorelaxation, indicating is absorbed chromophore medial layer. same degree obtained without adventitia when either one-half ring, or irradiated communication between smooth muscle cells spreads signal from area illuminated entire ring. mechanism using potential inhibitors. N-monomethyl-L-arginine N-amino-L-arginine, inhibitors nitric oxide synthase, did alter nor indomethacin, an inhibitor cyclooxygenase, zinc protoporphyrin, heme oxygenase.